Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fas antigen (Fas Ag; CD95) is a cell surface molecule that can mediate apoptosis. Bcl-2 is a cytoplasmic molecule that prolongs cellular survival by inhibiting apoptosis. To investigate the role of both molecules in hematopoiesis, we evaluated the expression of Fas Ag and Bcl-2 on CD34+ hematopoietic progenitor cells expanded in vitro. CD34+ cells isolated from bone marrow were cultured in iscove's modified Dulbecco's medium supplemented with 10% fetal calf serum, 1% bovine serum albumin, 50 ng/mL stem cell factor, 50 ng/mL interleukin-3 (IL-3), 50 ng/mL IL-6, 100 ng/mL granulocyte colony-stimulating factor, and 3 U/mL erythropoietin for 7 days. Colony-forming unit of granulocytes/macrophages (CFU-GM) and burst-forming unit of erythroids (BFU-E) were expanded 6.9-fold and 8.8-fold in number at day 5 of culture, respectively. Freshly isolated CD34+ cells did not express Fas Ag, whereas approximately half of them expressed Bcl-2. CD34+ cells cultured with hematopoietic growth factors gradually became positive for Fas Ag and rapidly lost Bcl-2 expression. Furthermore, apoptosis was induced in the cultured CD34+ population when anti-Fan antibody (IgM; 1 microgram/mL) was added, as shown by significant decrease in the number of viable cells, morphologic changes, induction of DNA fragmentation, and significant decrease in the number of clonogenic progenitor cells including CFU. GM and BFU-E. These results indicate that functional expression of Fas Ag is induced on CD34+ cells expanded in vitro in the presence of hematopoietic growth factors. Induction of Fas Ag and downregulation of Bcl-2 may be expressed as part of the differentiation program of hematopoietic cells and may be involved in the regulation of hematopoiesis.
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PMID:In vitro expansion of hematopoietic progenitor cells induces functional expression of Fas antigen (CD95). 887 83

The proto-oncogene product c-Fos, a component of the transcription factor AP-1, is induced in early B lineage cells. To investigate a role of c-Fos in early B cell development, fetal liver (FL) cells from transgenic mice carrying an IFN-alphabeta (IFN)-inducible c-fos gene (Mx-c-fosD) were cultured on a stromal cell layer with IL-7. Although B lineage cells normally developed in the Mx-c-fosD FL cell culture, the development was perturbed by the addition of IFN at the beginning of culture. When IFN was added in the FL culture after B lineage cells developed, pro-B (B220+,CD43+) cells were selectively dying by apoptosis within 48 h after IFN stimulation. This apoptosis was intrinsically induced in the pro-B cells that overexpressed c-fos when the Mx-c-fosD FL (H-2Kb) cells were cocultured with the normal C3H FL (H-2Kk) cells. The molecular basis of the apoptosis was investigated by examining expression of the genes that regulate apoptosis. The IFN stimulation did not modulate expression of Bcl-2 and Fas in early B lineage cells from the Mx-c-fosD FL culture. However, Rag-2 was down-regulated in these cells within 12 h after IFN stimulation. These results suggest that the c-Fos plays a causal role in deletion of pro-B cells with nonfunctional Ag receptor.
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PMID:Overexpression of c-Fos induces apoptosis of CD43+ pro-B cells. 889 9

Fas-mediated apoptosis plays an important role in regulating the immune response in peripheral T cells. Restimulation of T cell blasts up-regulates Fas and Fas ligand expression, with subsequent interaction leading to cell death. Overexpression of Bcl-2 in tumor cells blocks apoptosis induced by many stimuli, but inhibition of Fas-mediated killing has not been consistently observed. To examine the behavior of Bcl-2 in normal cells, T cell blasts were transiently transfected with Bcl-2 and related gene products to determine the effect on apoptotic signaling. Transient overexpression of Bcl-2 in mouse and human T cell blasts did not block Fas-mediated apoptosis, whereas etoposide- and glucocorticoid-induced cytotoxicity was potently inhibited. Expression of Bcl-xL and adenovirus E1B 19K did not interfere with anti-Fas killing. In contrast, interleukin-1beta-converting enzyme family protease inhibitors Ac-DEVD-CHO and CrmA blocked Fas-mediated apoptosis. These results suggest that peripheral T cells use distinct apoptosis signaling pathways with differential sensitivity to Bcl-2 and interleukin-1beta-converting enzyme family protease inhibitors. Since T cells normally express Bcl-2 and Bcl-xL following activation, their inability to block Fas-mediated apoptosis may allow for the elimination of self-reactive cells and the appropriate regulation of immune responses.
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PMID:Apoptosis signaling pathways in normal T cells: differential activity of Bcl-2 and IL-1beta-converting enzyme family protease inhibitors on glucocorticoid- and Fas-mediated cytotoxicity. 889 14

IL-2 administration in vivo has been shown to increase CD4+ T cell counts in HIV+ patients. We have previously reported that PBMC from HIV-infected patients undergo marked spontaneous apoptosis in vitro. In this study, we examined the effect of IL-2 added in vitro upon culture-induced apoptosis in PBMC from 80 HIV-infected patients by flow cytometry. IL-2 at concentrations of > or = 10 U/ml significantly reduced spontaneous apoptosis in CD3+ T lymphocytes in patients but not in healthy volunteers. Interestingly, we observed that Bcl-2 expression in patient lymphocytes decreased rapidly upon in vitro culture while that in cells of healthy volunteers was relatively unaffected. The most significant decrease in Bcl-2 expression was noted in the apoptotic cell population. The IL-2-mediated reduction in lymphocyte apoptosis was found to be associated with the blocking of this culture-induced down-modulation of Bcl-2 expression. IL-2 did not induce significant expansion of lymphocytes during the culture period nor did it affect Fas Ag expression in patient cells, which were already expressing Fas maximally. These findings strongly suggest that IL-2 mediates its apoptosis-blocking effects via suppressing down-modulation of Bcl-2. Our findings also provide an experimental basis for the ongoing therapies utilizing this cytokine for slowing HIV disease progression.
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PMID:IL-2 rescues in vitro lymphocyte apoptosis in patients with HIV infection: correlation with its ability to block culture-induced down-modulation of Bcl-2. 889 56

In situ expression of apoptosis and its related antigens has rarely been evaluated in human liver tumors. Therefore, investigation using in situ nick end-labeling and immunohistochemical methods of the in situ expression of apoptosis, proliferating cells, and apoptosis-related antigens in 7 normal livers, 20 cholangiocarcinomas (CC) and 17 hepatocellular carcinomas (HCC) was done. Apoptotic cells as determined by the nick end-labeling method and proliferating cell nuclear antigen-positive cells were present in all specimens, and the percentage of them was significantly higher in CC than in HCC. Bcl-2 protein was present only in one CC and one HCC, but was occasionally noted in bile ducts in non-cancerous livers. C-myc and Fas antigens were not found in any of the cases. Lewisy antigen was expressed in 8 CC, but was absent in the other cases although bile ducts in non-cancerous livers frequently expressed Lewisy. p53 protein was present in 8 CC, but was absent in the other cases. Serial section observations showed that apoptotic cancer cells were consistently negative for proliferating cell nuclear antigen; bcl-2-positive cells did not show apoptosis; p53-positive cancer cells showed apoptosis. Some Lewisy-positive cancer cells showed apoptosis, while others did not. These data suggest that apoptosis and cell proliferation are involved in CC and HCC, and their degree is more severe in CC than in HCC. p53 protein (stimulative) may regulate apoptosis in some cases, whereas c-myc, Fas and Lewisy are not related to apoptosis in CC and HCC in vivo. Many other factors may regulate apoptosis in CC and HCC in vivo.
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PMID:Expression of apoptosis, proliferating cell nuclear antigen, and apoptosis-related antigens (bcl-2, c-myc, Fas, Lewis(y) and p53) in human cholangiocarcinomas and hepatocellular carcinomas. 891 46

CD28 on T cells provides a potent costimulatory signal for T cell activation. Down-regulation of CD28 on peripheral T cells has been reported in certain clinical conditions, but full studies on the mechanism and biological significance have not been performed. Our extensive phenotype analysis of peripheral blood lymphocytes (PBL) from SLE patients revealed that the absolute number of CD28+ T cells of both CD4 and CD8 phenotypes was selectively decreased, while that of CD28- T cells was maintained. CD28+ T cells from SLE patients exhibited mostly normal proliferative responses to both CD28-dependent and -independent stimulations. In contrast, CD28- T cells were hyporesponsive to anti-CD3 stimulation in both SLE and normal controls. These results implied that the selective decrease of CD28+ T cells in SLE does not result from a hyporesponsiveness of CD28+ T cells. To investigate the reason for the selective loss of CD28+ T cells, we determined the appearance of apoptotic cells in culture with or without anti-CD3 stimulation. Apoptotic cells defined by merocyanine (MC)540 were gradually increased from 12 h to 24 h. Anti-CD3-induced apoptosis of CD28+ T cells was significantly accelerated in SLE, whereas apoptosis of CD28- T cells was hardly detected in both SLE and normal controls. Comparative analysis between CD28+ and CD28- T cells on CD95 (Fas) and Bcl-2 expression, which are related to activation-induced cell death (AICD), did not show a major difference, although CTLA4, which has been demonstrated to transmit an apoptosis-inducing signal, was expressed only on CD28+ T cells. Our results suggest that CD28-mediated costimulation influences T cell susceptibility to AICD and may be involved in T cell lymphopenia in SLE.
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PMID:Preferential elimination of CD28+ T cells in systemic lupus erythematosus (SLE) and the relation with activation-induced apoptosis. 891 66

Immunostaining of Bcl-2 protein which represses apoptosis was performed on 178 biopsied human pathologic muscles and 10 control muscles by the ABC method using two monoclonal anti-Bcl-2 antibodies. Bcl-2 in control muscles was positive mainly in nuclear membrane and cytoplasm in type 2 fibers (especially type 2B fibers), and negative in type 1 fibers. In myopathies, it was not expressed in type 2C (regenerating) fibers, and its expression in atrophic fibers such as forming pyknotic nuclear clumps was strong. In inflammatory myopathies, expression was observed in infiltrating lymphocytes, and especially in dermatomyositis in atrophic fibers facing perimysium. In mitochondrial myopathies, the positivity was observed only in type 2 ragged-red fibers. In muscles of neurogenic disorders, both small angulated fibers and atrophic grouped fibers were strongly positive. Western blot analysis using anti-Bcl-2 antibody showed a single band at 26 kDa in control and diseased skeletal muscles. Compared to immunostaining of Fas antigen in serial sections, both Bcl-2 and Fas were expressed in same atrophic fibers in distal myopathy with rimmed vacuoles. In myotonic dystrophy, they were often expressed in type 2 fibers containing internal nucleus. In carriers of Duchenne dystrophy, Fas-positive but Bcl-2 negative fibers were observed in same dystrophin-negative fibers. In conclusion, expression of Bcl-2 in skeletal muscles might suggest that Bcl-2 plays a role on surviving muscle fibers.
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PMID:[Immunostaining of anti-Bcl-2 antibody in diseased human muscles]. 893 93

In the study presented here, we investigated the possible interactions between CD95 (Fas/APO-1) and Bcl-2 by studying the effects of Bcl-2 on the modulation of cellular pathways activated by CD95 using HeLa cells as a model system. We report that stable expression of Bcl-2 in HeLa cells is associated with multiple phenotypic changes. Treatment of HeLa cells with anti-CD95 monoclonal antibody (mAb) resulted in preferential degradation of lamin B compared with lamins A and C. Significant lamin B degradation was detected as early as 1 h after anti-CD95 mAb treatment. In contrast, lamins A and C as well as actin remained unchanged until 4 h after treatment with anti-CD95 mAb, a time point that correlated with the period of DNA fragmentation. These results indicate that selective degradation of lamin B is an early cellular event in response to activation of the CD95 pathway and that it precedes DNA fragmentation. Overexpression of Bcl-2 resulted in prevention of lamin B degradation and DNA fragmentation into oligonucleosome fragments in response to the apoptotic signal by anti-CD95 mAb. In addition, in Bcl-2-overexpressing cells that were protected against apoptosis, anti-CD95 mAb-induced cleavage of poly(ADP-ribose) polymerase was completely blocked. Overexpression of Bcl-2 also resulted in restoration of the CD95-mediated signaling pathway involving activation of the transcription factor NF-kappaB (p50/RelA). These findings suggest that Bcl-2 prevents apoptosis in part by preventing the degradation of major nuclear polypeptides such as lamin B and poly(ADP-ribose) polymerase. In addition, our results demonstrate that CD95-mediated signaling involves activation of NF-kappaB (p50/RelA).
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PMID:Bcl-2 prevents CD95 (Fas/APO-1)-induced degradation of lamin B and poly(ADP-ribose) polymerase and restores the NF-kappaB signaling pathway. 893 96

Neonatal exposure to a synthetic estrogen, diethylstilbestrol (DES), induces the ovary-independent persistent proliferation of vaginal epithelium in mice. Mouse vagina at the estrous stage in the normal estrous cycle shows 10 to 15 layers of epithelium with superficial keratinized layers, and ovariectomy induces a decrease of these epithelial cell layers and lymphocyte infiltration. Thus, cell proliferation and regression of vaginal epithelium are ovary dependent. Neonatally DES-treated mouse vagina showed the same phenotype as normal mouse vagina at the estrous stage, but ovariectomy did not induce a decrease of epithelial cell layers or a lymphocyte infiltration, and there was persistent proliferation of vaginal epithelium even after ovariectomy. In addition, apoptotic cell death characterized by oligonucleosomal DNA fragmentation, Fas expression, and Bcl-2 downregulation were induced after ovariectomy in normal mouse vagina, but not in DES-treated mouse vagina. These results suggest that neonatal DES-exposure in mice prevents vaginal Fas-mediated apoptosis following the downregulation of Bcl-2, and these abnormalities in expression are involved in persistent proliferation of the vaginal epithelium.
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PMID:Effect of neonatal exposure to DES in Fas and Bcl-2 expression in the adult mouse vagina and approach to the DES syndrome. 894 60

Fas is a cell-surface protein belonging to the tumor necrosis factor (TNF) receptor family, whereas the Fas ligand (FasL) is a member of the TNF family. FasL binds to Fas, which results in target cell apoptosis. A family of cysteine proteases is sequentially activated to proceed the Fas-induced apoptosis, whereas Bcl-2 inhibits the process. FasL is expressed in activated T cells and natural killer (NK) cells, and works as an effector of these cytotoxic cells to remove the cells infected by virus, or cancer cells. The Fas system is also involved in peripheral clonal deletion, and/or the activation-induced suicide of T cells to down-regulate the immune reaction. Mouse mutations of lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld), which cause lymphadenopathy and splenomegaly, and accelerate autoimmune disease, are loss-of-function mutations in the Fas and FasL genes, respectively. Moreover, the Fas-null mice established by gene targeting showed hyperplasia in the liver, suggesting that the Fas system is involved in turn-over of senescent hepatocytes.
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PMID:A death factor--the other side of the coin. 895 Apr 63


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